I joined/uploaded 3 to Pexels :-)

Great resource, Diego! I only knew of Pixabay. I personally don't share other photographer's work on my instagram account but I can certainly see how this is useful in many other applications. I went ahead and created an account and uploaded three images to Pexels: https://www.pexels.com/u/kris-petersen-34366/ #PayItForward